Anchored mediator enabling shuttle-free redox mediation in lithium-oxygen batteries.

Redox mediators (RMs) are considered an effective countermeasure to reduce the large polarization in lithium-oxygen batteries. Nevertheless, achieving sufficient enhancement of the cyclability is limited by the trade-offs of freely mobile RMs, which are beneficial for charge transport but also trigger the shuttling phenomenon. Here, we successfully decoupled the charge-carrying redox property of RMs and shuttling phenomenon by anchoring the RMs in polymer form, where physical RM migration was replaced by charge transfer along polymer chains. Using a model system of a polymer, PTMA (2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate), based on the well-known RM tetramethylpiperidinyloxyl (TEMPO), it is demonstrated that PTMA is capable of functioning as a stationary RM, preserving the redox activity of TEMPO. The efficiency of RM-mediated Li 2 O 2 decomposition remains remarkably stable without the consumption of oxidized RMs or degradation of the lithium anode, resulting in marked improvement of the performance of the lithium-oxygen cell.